Cast irons flame hardening

PISTON RINGS are normally cast-iron of the single-piece snap-ring type, although other materials may be used when conditions require. PISTON ROD is carbon-steel, flame-hardened over packing travel area. 

Uses Hardening alloy for lead (solder, pewter, white metal, shotgun pellets) lead-antimony-tin alloys (battery plates, casting) lead-antimony alloys (battery plates, roofing, radiation protection, ammunition) bearing metal semiconductor technology pyrotechnics flame retardant in plastics cast iron ingred. type metal solder collapsible tubes and foil sheet and pipe... 

The flame-hardening process is used for a wide variety of applications. These include (1) parts that are so large that conventional furnace treatments are impractical or uneconomical, (2) prevention of detrimental treatment of the entire component when only small segments of die part require heat treatment, and (3) use of less costly material to obtain the desired surface properties where alloyed steels would be normally applied. Flame hardening is limited to hardenable steels (wrought or cast) and cast iron. Typical hardnesses obtained for the flame-hardened grades depend on the quench media (Table 1). The practical level of minimum surface hardness attainable with water quenching for various carbon contents is shown in Fig. 1. 

Table 1 Response of steels and cast irons to flame hardening...

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